package io.emqx.stream.client.mqtt;

import java.io.IOException;
import java.sql.Timestamp;

import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.MqttCallback;
import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;

/**
 * A sample application that demonstrates how to use the Paho MQTT v3.1 Client blocking API.
 *
 * It can be run from the command line in one of two modes:
 *  - as a publisher, sending a single message to a topic on the server
 *  - as a subscriber, listening for messages from the server
 *
 *  There are three versions of the sample that implement the same features
 *  but do so using using different programming styles:
 *  <ol>
 *  <li>Sample (this one) which uses the API which blocks until the operation completes</li>
 *  <li>SampleAsyncWait shows how to use the asynchronous API with waiters that block until
 *  an action completes</li>
 *  <li>SampleAsyncCallBack shows how to use the asynchronous API where events are
 *  used to notify the application when an action completes<li>
 *  </ol>
 *
 *  If the application is run with the -h parameter then info is displayed that
 *  describes all of the options / parameters.
 */
public class Sample implements MqttCallback {

  /**
   * The main entry point of the sample.
   *
   * This method handles parsing of the arguments specified on the
   * command-line before performing the specified action.
   */
  public static void main(String[] args) {

    // Default settings:
    boolean quietMode 	= false;
    String action 		= "publish";
    String topic 		= "";
    String message 		= "Message from blocking Paho MQTTv3 Java client sample";
    int qos 			= 2;
    String broker 		= "172.16.0.4";
    int port 			= 1883;
    String clientId 	= null;
    String subTopic		= "Sample/#";
    String pubTopic 	= "Sample/Java/v3";
    boolean cleanSession = true;			// Non durable subscriptions
    boolean ssl = false;
    String password = null;
    String userName = null;
    // Parse the arguments -
    for (int i=0; i<args.length; i++) {
      // Check this is a valid argument
      if (args[i].length() == 2 && args[i].startsWith("-")) {
        char arg = args[i].charAt(1);
        // Handle arguments that take no-value
        switch(arg) {
          case 'h': case '?':	printHelp(); return;
          case 'q': quietMode = true;	continue;
        }

        // Now handle the arguments that take a value and
        // ensure one is specified
        if (i == args.length -1 || args[i+1].charAt(0) == '-') {
          System.out.println("Missing value for argument: "+args[i]);
          printHelp();
          return;
        }
        switch(arg) {
          case 'a': action = args[++i];                 break;
          case 't': topic = args[++i];                  break;
          case 'm': message = args[++i];                break;
          case 's': qos = Integer.parseInt(args[++i]);  break;
          case 'b': broker = args[++i];                 break;
          case 'p': port = Integer.parseInt(args[++i]); break;
          case 'i': clientId = args[++i];				  break;
          case 'c': cleanSession = Boolean.valueOf(args[++i]);  break;
          case 'k': System.getProperties().put("javax.net.ssl.keyStore", args[++i]); break;
          case 'w': System.getProperties().put("javax.net.ssl.keyStorePassword", args[++i]); break;
          case 'r': System.getProperties().put("javax.net.ssl.trustStore", args[++i]); break;
          case 'v': ssl = Boolean.valueOf(args[++i]); break;
          case 'u': userName = args[++i];               break;
          case 'z': password = args[++i];               break;
          default:
            System.out.println("Unrecognised argument: "+args[i]);
            printHelp();
            return;
        }
      } else {
        System.out.println("Unrecognised argument: "+args[i]);
        printHelp();
        return;
      }
    }

    // Validate the provided arguments
    if (!action.equals("publish") && !action.equals("subscribe")) {
      System.out.println("Invalid action: "+action);
      printHelp();
      return;
    }
    if (qos < 0 || qos > 2) {
      System.out.println("Invalid QoS: "+qos);
      printHelp();
      return;
    }
    if (topic.equals("")) {
      // Set the default topic according to the specified action
      if (action.equals("publish")) {
        topic = pubTopic;
      } else {
        topic = subTopic;
      }
    }

    String protocol = "tcp://";

    if (ssl) {
      protocol = "ssl://";
    }

    String url = protocol + broker + ":" + port;

    if (clientId == null || clientId.equals("")) {
      clientId = "SampleJavaV3_"+action;
    }

    // With a valid set of arguments, the real work of
    // driving the client API can begin
    try {
      // Create an instance of this class
      Sample sampleClient = new Sample(url, clientId, cleanSession, quietMode,userName,password);

      // Perform the requested action
      if (action.equals("publish")) {
        sampleClient.publish(topic,qos,message.getBytes());
      } else {
        sampleClient.subscribe(topic,qos);
      }
    } catch(MqttException me) {
      // Display full details of any exception that occurs
      System.out.println("reason "+me.getReasonCode());
      System.out.println("msg "+me.getMessage());
      System.out.println("loc "+me.getLocalizedMessage());
      System.out.println("cause "+me.getCause());
      System.out.println("excep "+me);
      me.printStackTrace();
    }
  }

  // Private instance variables
  private MqttClient 			client;
  private final String 				brokerUrl;
  private final boolean 			quietMode;
  private MqttConnectOptions 	conOpt;

  /**
   * Constructs an instance of the sample client wrapper
   * @param brokerUrl the url of the server to connect to
   * @param clientId the client id to connect with
   * @param cleanSession clear state at end of connection or not (durable or non-durable subscriptions)
   * @param quietMode whether debug should be printed to standard out
   * @param userName the username to connect with
   * @param password the password for the user
   */
  private Sample(String brokerUrl, String clientId, boolean cleanSession, boolean quietMode, String userName, String password) {
    this.brokerUrl = brokerUrl;
    this.quietMode = quietMode;
    //This sample stores in a temporary directory... where messages temporarily
    // stored until the message has been delivered to the server.
    //..a real application ought to store them somewhere
    // where they are not likely to get deleted or tampered with
    //String tmpDir = System.getProperty("java.io.tmpdir");
    //MqttDefaultFilePersistence dataStore = new MqttDefaultFilePersistence(tmpDir);

    try {
      // Construct the connection options object that contains connection parameters
      // such as cleanSession and LWT
      conOpt = new MqttConnectOptions();
      conOpt.setCleanSession(cleanSession);
      if(password != null ) {
        conOpt.setPassword(password.toCharArray());
      }
      if(userName != null) {
        conOpt.setUserName(userName);
      }

      // Construct an MQTT blocking mode client
      try {
        client = new MqttClient(this.brokerUrl,clientId);
      }catch(Exception exp) {
        exp.printStackTrace();
        throw exp;
      }


      // Set this wrapper as the callback handler
      client.setCallback(this);

    } catch (MqttException e) {
      e.printStackTrace();
      log("Unable to set up client: "+e.toString());
      System.exit(1);
    }
  }

  /**
   * Publish / send a message to an MQTT server
   * @param topicName the name of the topic to publish to
   * @param qos the quality of service to delivery the message at (0,1,2)
   * @param payload the set of bytes to send to the MQTT server
   */
  private void publish(String topicName, int qos, byte[] payload) throws MqttException {

    try {
      log("Connecting to "+brokerUrl + " with client ID "+client.getClientId());
      client.connect(conOpt);
      log("Connected");
    }catch(Exception exp) {
      exp.printStackTrace();
      throw exp;
    }


    String time = new Timestamp(System.currentTimeMillis()).toString();
    log("Publishing at: "+time+ " to topic \""+topicName+"\" qos "+qos);

    // Create and configure a message
    MqttMessage message = new MqttMessage(payload);
    message.setQos(qos);

    // Send the message to the server, control is not returned until
    // it has been delivered to the server meeting the specified
    // quality of service.
    client.publish(topicName, message);

    // Disconnect the client
    client.disconnect();
    log("Disconnected");
  }

  /**
   * Subscribe to a topic on an MQTT server
   * Once subscribed this method waits for the messages to arrive from the server
   * that match the subscription. It continues listening for messages until the enter key is
   * pressed.
   * @param topicName to subscribe to (can be wild carded)
   * @param qos the maximum quality of service to receive messages at for this subscription
   */
  private void subscribe(String topicName, int qos) throws MqttException {

    // Connect to the MQTT server
    client.connect(conOpt);
    log("Connected to "+brokerUrl+" with client ID "+client.getClientId());

    // Subscribe to the requested topic
    // The QoS specified is the maximum level that messages will be sent to the client at.
    // For instance if QoS 1 is specified, any messages originally published at QoS 2 will
    // be downgraded to 1 when delivering to the client but messages published at 1 and 0
    // will be received at the same level they were published at.
    log("Subscribing to topic \""+topicName+"\" qos "+qos);
    client.subscribe(topicName, qos);

    // Continue waiting for messages until the Enter is pressed
    log("Press <Enter> to exit");
    try {
      //noinspection ResultOfMethodCallIgnored
      System.in.read();
    } catch (IOException e) {
      //If we can't read we'll just exit
    }

    // Disconnect the client from the server
    client.disconnect();
    log("Disconnected");
  }

  /**
   * Utility method to handle logging. If 'quietMode' is set, this method does nothing
   * @param message the message to log
   */
  private void log(String message) {
    if (!quietMode) {
      System.out.println(message);
    }
  }

  /* Methods to implement the MqttCallback interface              */

  /**
   * @see MqttCallback#connectionLost(Throwable)
   */
  public void connectionLost(Throwable cause) {
    // Called when the connection to the server has been lost.
    // An application may choose to implement reconnection
    // logic at this point. This sample simply exits.
    log("Connection to " + brokerUrl + " lost!" + cause);
    System.exit(1);
  }

  /**
   * @see MqttCallback#deliveryComplete(IMqttDeliveryToken)
   */
  public void deliveryComplete(IMqttDeliveryToken token) {
    // Called when a message has been delivered to the
    // server. The token passed in here is the same one
    // that was passed to or returned from the original call to publish.
    // This allows applications to perform asynchronous
    // delivery without blocking until delivery completes.
    //
    // This sample demonstrates asynchronous deliver and
    // uses the token.waitForCompletion() call in the main thread which
    // blocks until the delivery has completed.
    // Additionally the deliveryComplete method will be called if
    // the callback is set on the client
    //
    // If the connection to the server breaks before delivery has completed
    // delivery of a message will complete after the client has re-connected.
    // The getPendingTokens method will provide tokens for any messages
    // that are still to be delivered.
  }

  /**
   * @see MqttCallback#messageArrived(String, MqttMessage)
   */
  public void messageArrived(String topic, MqttMessage message) {
    // Called when a message arrives from the server that matches any
    // subscription made by the client
    String time = new Timestamp(System.currentTimeMillis()).toString();
    System.out.println("Time:\t" +time +
            "  Topic:\t" + topic +
            "  Message:\t" + new String(message.getPayload()) +
            "  QoS:\t" + message.getQos());
  }

  /* End of MqttCallback methods                                  */
  /****************************************************************/

  private static void printHelp() {
    System.out.println(
            "Syntax:\n\n" +
                    "    Sample [-h] [-a publish|subscribe] [-t <topic>] [-m <message text>]\n" +
                    "            [-s 0|1|2] -b <hostname|IP address>] [-p <brokerport>] [-i <clientID>]\n\n" +
                    "    -h  Print this help text and quit\n" +
                    "    -q  Quiet mode (default is false)\n" +
                    "    -a  Perform the relevant action (default is publish)\n" +
                    "    -t  Publish/subscribe to <topic> instead of the default\n" +
                    "            (publish: \"Sample/Java/v3\", subscribe: \"Sample/#\")\n" +
                    "    -m  Use <message text> instead of the default\n" +
                    "            (\"Message from MQTTv3 Java client\")\n" +
                    "    -s  Use this QoS instead of the default (2)\n" +
                    "    -b  Use this name/IP address instead of the default (m2m.eclipse.org)\n" +
                    "    -p  Use this port instead of the default (1883)\n\n" +
                    "    -i  Use this client ID instead of SampleJavaV3_<action>\n" +
                    "    -c  Connect to the server with a clean session (default is false)\n" +
                    "     \n\n Security Options \n" +
                    "     -u Username \n" +
                    "     -z Password \n" +
                    "     \n\n SSL Options \n" +
                    "    -v  SSL enabled; true - (default is false) " +
                    "    -k  Use this JKS format key store to verify the client\n" +
                    "    -w  Passpharse to verify certificates in the keys store\n" +
                    "    -r  Use this JKS format keystore to verify the server\n" +
                    " If javax.net.ssl properties have been set only the -v flag needs to be set\n" +
                    "Delimit strings containing spaces with \"\"\n\n" +
                    "Publishers transmit a single message then disconnect from the server.\n" +
                    "Subscribers remain connected to the server and receive appropriate\n" +
                    "messages until <enter> is pressed.\n\n"
    );
  }

}